1. Field of the Invention
The present invention relates, in general, to air guns utilizing the action of compressed air and, more particularly, to a multifunctional air gun designed to selectively perform a sucking operation, a blowing operation, or the two operations at the same time as desired.
2. Description of the Prior Art
As well known to those skilled in the art, a plurality of machines utilizing the action of compressed air, for example, vacuum cleaners, blowers, air guns and air pumps, have been proposed and widely used. Conventional machines utilizing the action of compressed air are designed to perform an individual function. That is, vacuum cleaners or air guns are typically used for removing impurities, such as dust and dirty liquid, from desired objects in a variety of industrial areas, such as motor-maintenance areas. On the other hand, air pumps are typically used in changing the cutting oils in machine tools or in changing the engine oils in automobiles. In addition, the vacuum cleaners and the air guns may be used for removing a variety of impurities, such as dust and chips, generated during a cutting operation of machine tools.
However, the conventional machines utilizing the action of compressed air are not designed to perform a sucking operation and a blowing operation using one machine, but are designed to always perform only one of the two operations. This forces a user to purchase two machines, or a vacuum cleaner and an air gun, with excessive money paid for the machines, and forces the user to waste time while performing the two operations.
In an effort to overcome such a problem, a multifunctional air gun, designed to perform a sucking operation and a blowing operation, has been proposed and marketed by a Japanese company, Osawa Co., Ltd. However, Osawa's multifunctional air gun (hereinbelow, referred to simply as "the first conventional air gun") is problematic in that it is impossible to control the flow rate of compressed air in the air gun. In the first conventional air gun, a nozzle is set in a tubular body, acting as a compressed air passage sucking impurities into the gun, with a cap covering the nozzle. Six holes, individually having a diameter of 1.4 mm, are formed on an area between the nozzle and the cap, with the flow rate of compressed air being determined by the six holes.
That is, the first conventional air gun is not provided with a separate blowing device, but a blowing air control knob with a blowing pipe is provided at the top of the tubular body of the air gun. The above air gun thus has a desired blowing function in addition to a sucking function, and removes impurities through a sucking operation and a blowing operation.
However, the first conventional air gun is problematic in that the diameter of the six holes determining the flow rate of compressed air is not variable, but is fixed, and so it is impossible for a user to control the flow rate of compressed air, or the suction force of the air gun, when necessary. Therefore, the above air gun fails to effectively remove some impurities, such as large-sized particles and chips, from desired objects. Another problem experienced in the above multifunctional air gun resides in that the air gun is not designed to selectively perform either of the two operations, thus being regrettably limited in use. Particularly, it is impossible for the above air gun to remove impurities through a blowing operation.
The inventor of this invention proposed a multifunctional air gun provided with a blowing function in addition to a sucking function in Korean Utility Model Application No. 98-22,633.
The above Korean multifunctional air gun (hereinbelow, referred to simply as "the second conventional air gun") is designed to selectively perform either of the sucking and blowing operations or perform the two operations at the same time as desired. In addition, the second conventional air gun is designed to be controllable in the flow rate of compressed air when necessary. The second conventional air gun thus somewhat effectively overcomes the problems experienced in the first conventional air gun. However, this air gun is problematic in that it is provided with a plurality of separate valves giving inconvenience to users. Another problem of the second conventional air gun resides in that it has a complex construction, with an increased number of parts being easily broken. Due to the increased number of parts, the production cost is increased while manufacturing the multifunctional air guns.